This graph shows the beam spread of various grids when installed on a 7" reflector. The 11LTR is 28 degrees, so I would use the 30 degree zone for reference. As the distance doubles, so does the diameter.

Yes, an 11" reflector would have a slightly larger area than the 7", but at 65 feet it is irrelevant (it would be a 4" difference at any distance).